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KVM: x86: Delete duplicate documentation for KVM_X86_SET_MSR_FILTER

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Two copies of KVM_X86_SET_MSR_FILTER somehow managed to make it's way
into the documentation.  Remove one copy and merge the difference from
the removed copy into the copy that's being kept.

Fixes: fd49e8ee70 ("Merge branch 'kvm-sev-cgroup' into HEAD")
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Link: https://lore.kernel.org/r/20220712001045.2364298-2-aaronlewis@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Aaron Lewis 2022-07-12 00:10:44 +00:00 committed by Paolo Bonzini
parent db25eb87ad
commit b5cb32b16c
1 changed files with 6 additions and 107 deletions
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113
Documentation/virt/kvm/api.rst
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@ -4074,7 +4074,7 @@ Queues an SMI on the thread's vcpu.
4.97 KVM_X86_SET_MSR_FILTER
----------------------------
:Capability: KVM_X86_SET_MSR_FILTER
:Capability: KVM_CAP_X86_MSR_FILTER
:Architectures: x86
:Type: vm ioctl
:Parameters: struct kvm_msr_filter
@ -4173,8 +4173,10 @@ If an MSR access is not permitted through the filtering, it generates a
allows user space to deflect and potentially handle various MSR accesses
into user space.
If a vCPU is in running state while this ioctl is invoked, the vCPU may
experience inconsistent filtering behavior on MSR accesses.
Note, invoking this ioctl while a vCPU is running is inherently racy. However,
KVM does guarantee that vCPUs will see either the previous filter or the new
filter, e.g. MSRs with identical settings in both the old and new filter will
have deterministic behavior.
4.98 KVM_CREATE_SPAPR_TCE_64
----------------------------
@ -5287,110 +5289,7 @@ KVM_PV_DUMP
authentication tag all of which are needed to decrypt the dump at a
later time.
4.126 KVM_X86_SET_MSR_FILTER
----------------------------
:Capability: KVM_CAP_X86_MSR_FILTER
:Architectures: x86
:Type: vm ioctl
:Parameters: struct kvm_msr_filter
:Returns: 0 on success, < 0 on error
::
struct kvm_msr_filter_range {
#define KVM_MSR_FILTER_READ (1 << 0)
#define KVM_MSR_FILTER_WRITE (1 << 1)
__u32 flags;
__u32 nmsrs; /* number of msrs in bitmap */
__u32 base; /* MSR index the bitmap starts at */
__u8 *bitmap; /* a 1 bit allows the operations in flags, 0 denies */
};
#define KVM_MSR_FILTER_MAX_RANGES 16
struct kvm_msr_filter {
#define KVM_MSR_FILTER_DEFAULT_ALLOW (0 << 0)
#define KVM_MSR_FILTER_DEFAULT_DENY (1 << 0)
__u32 flags;
struct kvm_msr_filter_range ranges[KVM_MSR_FILTER_MAX_RANGES];
};
flags values for ``struct kvm_msr_filter_range``:
``KVM_MSR_FILTER_READ``
Filter read accesses to MSRs using the given bitmap. A 0 in the bitmap
indicates that a read should immediately fail, while a 1 indicates that
a read for a particular MSR should be handled regardless of the default
filter action.
``KVM_MSR_FILTER_WRITE``
Filter write accesses to MSRs using the given bitmap. A 0 in the bitmap
indicates that a write should immediately fail, while a 1 indicates that
a write for a particular MSR should be handled regardless of the default
filter action.
``KVM_MSR_FILTER_READ | KVM_MSR_FILTER_WRITE``
Filter both read and write accesses to MSRs using the given bitmap. A 0
in the bitmap indicates that both reads and writes should immediately fail,
while a 1 indicates that reads and writes for a particular MSR are not
filtered by this range.
flags values for ``struct kvm_msr_filter``:
``KVM_MSR_FILTER_DEFAULT_ALLOW``
If no filter range matches an MSR index that is getting accessed, KVM will
fall back to allowing access to the MSR.
``KVM_MSR_FILTER_DEFAULT_DENY``
If no filter range matches an MSR index that is getting accessed, KVM will
fall back to rejecting access to the MSR. In this mode, all MSRs that should
be processed by KVM need to explicitly be marked as allowed in the bitmaps.
This ioctl allows user space to define up to 16 bitmaps of MSR ranges to
specify whether a certain MSR access should be explicitly filtered for or not.
If this ioctl has never been invoked, MSR accesses are not guarded and the
default KVM in-kernel emulation behavior is fully preserved.
Calling this ioctl with an empty set of ranges (all nmsrs == 0) disables MSR
filtering. In that mode, ``KVM_MSR_FILTER_DEFAULT_DENY`` is invalid and causes
an error.
As soon as the filtering is in place, every MSR access is processed through
the filtering except for accesses to the x2APIC MSRs (from 0x800 to 0x8ff);
x2APIC MSRs are always allowed, independent of the ``default_allow`` setting,
and their behavior depends on the ``X2APIC_ENABLE`` bit of the APIC base
register.
If a bit is within one of the defined ranges, read and write accesses are
guarded by the bitmap's value for the MSR index if the kind of access
is included in the ``struct kvm_msr_filter_range`` flags. If no range
cover this particular access, the behavior is determined by the flags
field in the kvm_msr_filter struct: ``KVM_MSR_FILTER_DEFAULT_ALLOW``
and ``KVM_MSR_FILTER_DEFAULT_DENY``.
Each bitmap range specifies a range of MSRs to potentially allow access on.
The range goes from MSR index [base .. base+nmsrs]. The flags field
indicates whether reads, writes or both reads and writes are filtered
by setting a 1 bit in the bitmap for the corresponding MSR index.
If an MSR access is not permitted through the filtering, it generates a
#GP inside the guest. When combined with KVM_CAP_X86_USER_SPACE_MSR, that
allows user space to deflect and potentially handle various MSR accesses
into user space.
Note, invoking this ioctl with a vCPU is running is inherently racy. However,
KVM does guarantee that vCPUs will see either the previous filter or the new
filter, e.g. MSRs with identical settings in both the old and new filter will
have deterministic behavior.
4.127 KVM_XEN_HVM_SET_ATTR
4.126 KVM_XEN_HVM_SET_ATTR
--------------------------
:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO